The communication infrastructure has implemented number portability to allow a user to keep their telephone number when they change communication service providers. Prior to the change of service providers, the communication infrastructure processes the user's telephone number to route calls to a home switch that serves the user's telephone. After the change, a new home switch will serve the user's telephone, and this new home switch has a route number. To implement number portability, a number portability database stores the user's telephone number in association with the route number for the new home switch. When a call is subsequently placed to the user's telephone number, the communication infrastructure transfers a message with the user's telephone number to the number portability database, and the number portability database returns a message with the route number for the new home switch. The communication infrastructure then processes the route number to route the call to the new home switch that serves the user's telephone.
The communication infrastructure has also implemented user mobility to allow the user to move around and receive calls at various locations. If the user moves to a remote location that is served by a remote switch, then the remote switch transfers the user's telephone number and a route number for the remote switch to a user mobility database. When a call is placed to the user's telephone number, the communication infrastructure routes the call to the user's home switch. If the user is not registered with the home switch, the home switch transfers a message with the user's telephone number to the user mobility database, and the user mobility database returns a message with the route number for the remote switch. The communication infrastructure then processes the route number for the remote switch to route the call from the home switch to the remote switch that currently serves the user's telephone.
On a call to a mobile user who has ported their telephone number and who is currently at a remote location, the communication infrastructure transfers a message with the user's telephone number to the number portability database, and the number portability database returns a message with a route number for the user's new home switch. The communication infrastructure typically routes the call to the new home switch based on the route number. The new home switch then transfers another message with the user's telephone number to the user mobility database, and the user mobility database returns a message with another route number for a remote switch currently serving the user. The communication infrastructure then processes the other route number to route the call to the remote switch.